A fiber-optic lighted forceps fluorescence lifetime detection apparatus

Abstract

The utility model provides a kind of optical fiber optical tweezers fluorescence lifetime detection equipment, by the light beam emitted by light source is divided into two ways, using the first optical fiber coupler to the two-way light signal received is coupled, and the light signal after coupling is transmitted to the optical fiber circulator connected, transmission to displacement control assembly by optical fiber circulator. Displacement control assembly utilizes one-way light signal to carry out target micro-particle capture, utilizes another light beam corresponding light signal to excite target micro-particle to generate excitation fluorescence signal, utilizes detection assembly to carry out photon number detection to excitation fluorescence signal, determines the fluorescence lifetime of target micro-particle. The utility model equipment can be realized in flexible control micro-particle, and the fluorescence lifetime of micro-particle is detected, and the utility model is more simple and efficient, applicable to precision large instrument to carry out ultrafast signal detection.

Description

Technical Field

[0001] This utility model relates to the field of microscale manipulation technology, and in particular to a fiber optic tweezers fluorescence lifetime detection device. Background Technology

[0002] Fiber tweezers fluorescence lifetime detection is a technique that combines fiber tweezers technology with fluorescence lifetime detection. While manipulating particles with fiber tweezers, the particles are excited by a laser of a specific wavelength to produce fluorescence. Then, the fluorescence decay process is measured by a detection system to obtain fluorescence lifetime information.

[0003] Current fiber optic tweezers fluorescence lifetime probing techniques typically require the integration of microchannels or microfluidics for multi-dimensional controllable manipulation. However, the fabrication of microfluidic control devices is complex, and as independent devices from optical fibers, the system suffers from low optical coupling efficiency and integration, thus hindering efficient particle or cell manipulation. Furthermore, methods using multiple single-mode fibers or spliced ​​fiber arrays for optical trapping suffer from low maneuverability due to the need to operate multiple fibers. Therefore, existing methods cannot achieve flexible manipulation of microparticles or cells for fluorescence lifetime probing.

[0004] Therefore, the existing technology needs further improvement. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a fiber optic tweezers fluorescence lifetime detection device, which uses a multimode fiber loop combination to achieve multi-wavelength incident light, and uses multi-wavelength beams to simultaneously realize fluorescence lifetime detection and microscale optical manipulation.

[0006] In a first aspect, this application provides a fiber optic tweezers fluorescence lifetime detection device, comprising:

[0007] A light source assembly for emitting a first beam and a second beam with different wavelengths;

[0008] The first objective lens and the second objective lens are respectively disposed in the optical paths of the first beam and the second beam, and are used to collect the optical signals of the first beam and the second beam, and transmit the collected optical signals to the first fiber coupler;

[0009] The first fiber coupler is used to couple the optical signals corresponding to the first beam and the second beam received, and to transmit the coupled optical signals to the connected fiber optic circulator.

[0010] The fiber optic circulator is used to transmit the optical signal corresponding to the first beam and the optical signal corresponding to the second beam to the displacement control component.

[0011] The displacement control component has an optical fiber end for capturing target microparticles. The target microparticles are captured by a high-order focused beam formed by the optical signal corresponding to the first beam at the optical fiber end. Under the illumination of the optical signal corresponding to the second beam, the target microparticles generate an excitation fluorescence signal, which is transmitted to the second optical fiber coupler via the optical fiber circulator.

[0012] The detection component is connected to the output end of the second fiber coupler and is used to receive the excitation fluorescence signal output by the second fiber coupler, and to detect the number of photons in the excitation fluorescence signal to determine the fluorescence lifetime of the target microparticle.

[0013] Optionally, the light source assembly includes: a light source, a parallel light transmission system, a frequency doubling crystal element, and a semi-reflective mirror;

[0014] The light source is used to emit a femtosecond laser beam;

[0015] The parallel light transmission system includes a first lens and a second lens, which together form a 4f system. The frequency doubling crystal element is located between the first lens and the second lens. The first lens, the frequency doubling crystal element, and the second lens are arranged sequentially in the optical path of the femtosecond laser beam to parallelize and frequency double the femtosecond laser beam, and output a mixed beam containing two different wavelengths.

[0016] The semi-reflective lens is disposed in the optical path of the mixed beam to split the two different wavelength optical signals in the mixed beam into two beams by transmission and reflection, respectively, to obtain the first beam and the second beam.

[0017] Optionally, the system is further provided with a reflector;

[0018] The reflector is positioned in the optical path of the first beam transmitted through the semi-reflective lens, and reflects the first beam to the first objective lens.

[0019] Optionally, the displacement control component includes an optical fiber end cap, a microscopic imaging component, and a position control platform;

[0020] The microscopic imaging component is used to convert the optical signal corresponding to the first beam output from the fiber optic circulator into an electrical signal to capture image information within the target area.

[0021] The position control platform is used to control the movement of the optical fiber tip within the target area, so that the optical fiber tip captures the target microparticles within the target area.

[0022] Optionally, the position control platform is a six-axis precision displacement stage, and the end face of the optical fiber tip has a three-dimensional structure.

[0023] Optionally, the detection component includes: a photomultiplier tube and a time-correlated single-photon counter;

[0024] The photomultiplier tube is used to amplify the received excitation fluorescence signal;

[0025] The time-correlated single-photon counter is used to measure the number of photons in the received excitation fluorescence signal, so as to determine the fluorescence lifetime of the target microparticle based on the number of received photons.

[0026] Optionally, the wavelength of the femtosecond laser beam is 800nm; the wavelength corresponding to the first beam is 800nm, and the wavelength corresponding to the second beam is 400nm.

[0027] Optionally, the focal length of the first lens and the second lens is 15mm.

[0028] Secondly, this application provides a method for detecting fluorescence lifetime using the aforementioned fiber optic tweezers fluorescence lifetime detection device, comprising:

[0029] The first objective lens and the second objective lens respectively collect the optical signals of the first beam and the second beam emitted by the light source assembly, and transmit the collected optical signals to the first fiber coupler; the first beam and the second beam have different wavelengths;

[0030] The first fiber coupler couples the optical signals corresponding to the first beam and the second beam received, and transmits the coupled optical signals to the displacement control component via the fiber optic circulator.

[0031] The displacement control component uses the optical signal corresponding to the first beam to capture the target microparticles. The target microparticles generate an excitation fluorescence signal under the illumination of the optical signal corresponding to the second beam. The excitation fluorescence signal is transmitted to the detection component via an optical fiber circulator and a second optical fiber coupler.

[0032] The fluorescence lifetime of the target microparticle is determined by detecting the number of photons in the excited fluorescence signal using a detection component.

[0033] Optionally, before the step of the first objective lens and the second objective lens respectively collecting the light signals of the first beam and the second beam emitted by the light source assembly, the method further includes:

[0034] The light source emits a femtosecond laser beam;

[0035] A parallel light transmission system placed in the optical path of a femtosecond laser beam parallelizes and frequency doubles the femtosecond laser beam, outputting a mixed beam containing two different wavelengths.

[0036] A semi-reflective lens placed in the optical path of the mixed beam splits the two different wavelengths of light signals in the mixed beam into two beams, resulting in a first beam and a second beam.

[0037] Beneficial effects:

[0038] This invention provides a fiber optic tweezers fluorescence lifetime detection device. It splits a light beam emitted by a light source assembly into a first beam and a second beam with different wavelengths. A first objective lens and a second objective lens collect the optical signals of the first and second beams, and transmit the collected signals to a first fiber optic coupler. The two optical signals are coupled using the first fiber optic coupler, and the coupled signals are transmitted to a connected fiber optic circulator. The fiber optic circulator transmits the optical signals corresponding to the two beams to a displacement control component. The displacement control component uses the optical signal corresponding to the first beam to capture target microparticles and uses the optical signal corresponding to the other beam to excite the target microparticles to generate an excitation fluorescence signal. The excitation fluorescence signal is transmitted to a second fiber optic coupler via the fiber optic circulator. A detection component detects the number of photons in the excitation fluorescence signal to determine the fluorescence lifetime of the target microparticles. This invention allows for the flexible manipulation of microparticles while detecting their fluorescence lifetime. Furthermore, this invention is simpler and more efficient, and is suitable for ultrafast signal detection in precision large instruments. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the fiber optic tweezers fluorescence lifetime detection device provided by this utility model;

[0040] Figure 2 This is a schematic diagram of a specific embodiment of the fiber optic tweezers fluorescence lifetime detection device provided by this utility model;

[0041] Figure 3 This is a flowchart illustrating the method steps for fluorescence lifetime detection using the fiber optic tweezers fluorescence lifetime detection device provided by this invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this utility model clearer and more explicit, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0043] Fluorescence lifetime probing, as a highly sensitive and time-resolution analytical technique, has demonstrated unique application value in multiple fields. Its core principle is to reveal molecular dynamics, interactions, and environmental information by measuring the time distribution of fluorescent molecules returning from excited states to ground states. It provides a powerful analytical tool in fields such as biomedicine and life sciences, materials science and nanotechnology, environmental monitoring and chemical analysis, and food and agriculture.

[0044] Optical fiber tweezers are optical tweezer systems based on fiber optic technology. They utilize optical fibers to transmit and focus laser beams, enabling non-contact capture and manipulation of minute particles. Compared to traditional optical tweezer systems based on microscope objectives, optical fiber tweezers offer advantages such as compact structure, high flexibility, and ease of integration, showing broad application prospects in fields such as biomedicine, micro / nano manipulation, and optomechanics.

[0045] The core of fiber optic tweezers lies in using optical fibers to transmit laser beams to tiny regions. Through special designs on the fiber endfaces (such as tapering or lensing), the laser beam is focused to the micrometer or even nanometer scale, creating a high-intensity gradient light field. When tiny particles (such as cells, bacteria, and microspheres) enter this light field, they are subjected to light radiation pressure, including scattering and gradient forces. The gradient force pulls the particles towards the region of maximum light intensity, while the scattering force tends to push the particles along the beam's propagation direction. By precisely controlling the parameters of the light field (such as power, wavelength, and polarization), stable particle capture and three-dimensional manipulation can be achieved.

[0046] Currently, many research institutions both domestically and internationally are conducting research on fiber optic tweezers. Some researchers have successfully manipulated mammalian cells using a single micro-fiber. Other research teams have stably captured small particles and red blood cells using two specially manufactured, opposing optical waveguide rings. Some teams have created simple single-fiber tweezers systems using tapered optical fibers, capturing polystyrene spheres and active yeast cells in fluid at the focal point of the beam, allowing the manipulated objects to move freely and synchronously with the tweezers. Domestic micro-nano optics teams were among the first to conduct research on optical tweezers and were the first to develop a three-dimensional fiber optic tweezers system. Therefore, how to utilize femtosecond lasers to establish a three-dimensional fiber optic tweezers system with built-in two-photon aggregation, enabling simultaneous ultrafast information detection under microscale manipulation, is a crucial scientific question.

[0047] Currently, fiber optic tweezers require microchannel or microfluidic technology for multidimensional controllable manipulation. Microfluidic devices are complex to fabricate, and as independent devices from optical fibers, their optical coupling efficiency and integration are low. Therefore, a simpler, more efficient, and highly integrated method for manipulating particles or cells is needed. In addition, researchers have used multiple single-mode fibers or spliced ​​fiber structures for optical trapping. However, while these methods can directly trap and manipulate tiny particles and cells using light scattering forces, their manipulative flexibility is limited, and their functionality is singular.

[0048] To overcome the aforementioned problems in the prior art, this application provides a fiber optic tweezers fluorescence lifetime detection device. This device splits a light beam emitted from a light source into two paths with different wavelengths, and uses a fiber optic circulator to transmit the two beams to a displacement control component. The displacement control component uses the optical signal corresponding to the first beam to capture target microparticles. Under the illumination of the optical signal corresponding to the second beam, the captured target microparticles generate an excitation fluorescence signal. The detection component detects the number of photons in the excitation fluorescence signal to determine the fluorescence lifetime of the target microparticles. The fluorescence lifetime detection device provided in this application can achieve uplink capture of various excitation lights and also realize the backlink of multiple detection signals, that is, simultaneously realize the manipulation of microparticles and the detection of fluorescence lifetime. It offers high operational flexibility and is suitable for ultrafast signal detection in precision large instruments.

[0049] The following description, in conjunction with the accompanying drawings, provides a more detailed account of the fiber optic tweezers fluorescence lifetime detection device provided in this application.

[0050] Firstly, this application provides a fiber optic tweezers fluorescence lifetime detection device, such as... Figure 1 As shown, it includes:

[0051] The light source assembly 10 is used to emit a first beam and a second beam with different wavelengths.

[0052] The light source assembly emits two beams with different wavelengths. The two beams of different wavelengths serve different purposes. To achieve beam emission, the light source assembly includes a light source for emitting the beams. Since the beams emitted by the light source are used to form optical tweezers for fluorescence lifetime detection, the light source used in this application is a femtosecond laser. A femtosecond laser is an ultrashort pulse laser with a pulse duration on the order of femtoseconds. It has characteristics such as high peak power, short pulse width, and low thermal effect, thus achieving clear imaging. In this embodiment, an 800nm ​​femtosecond laser light source is preferred. Since the light source assembly needs to emit two beams of different wavelengths, a nonlinear optical crystal can be used for frequency doubling to achieve a mixed beam containing two different wavelengths, which is then split using a filter or grating.

[0053] Furthermore, the femtosecond laser source used in this embodiment corresponds to a femtosecond pulse laser with a pulse width of 100 fs, a wavelength of 80 MHz, and a near-infrared wavelength of 805 nm. Because this type of femtosecond pulse laser has the characteristics of high repetition rate and short pulse width, it has the advantages of high time resolution, high signal-to-noise ratio and high measurement accuracy in ultrafast timescale detection.

[0054] The first objective lens 105 and the second objective lens 106 are respectively disposed in the optical paths of the first beam and the second beam, for collecting the optical signals of the first beam and the second beam, and transmitting the collected optical signals to the first fiber coupler 107.

[0055] The first beam and the second beam emitted by the light source assembly are collected by the first objective lens and the second objective lens, respectively, and the light signals collected by the first objective lens and the second objective lens are transmitted to the first fiber optic coupler.

[0056] Combination Figure 2 As shown, the first objective lens 105 is disposed in the optical path of the first beam to receive the optical signal corresponding to the first beam, and the second objective lens 106 is disposed in the optical path of the second beam to receive the optical signal corresponding to the second beam. Both the first objective lens 105 and the second objective lens 106 are connected to the first fiber optic coupler 107. Therefore, when the first objective lens 105 and the second objective lens 106 receive the optical signal, they transmit the received optical signal to the first fiber optic coupler 107.

[0057] The first fiber coupler 107 is used to couple the optical signals corresponding to the first beam and the second beam received, and to transmit the coupled optical signals to the connected fiber optic circulator 108.

[0058] One end of the first fiber coupler is connected to the first objective lens and the second objective lens, and the other end is connected to the fiber optic circulator. When the optical signals of the first beam and the second beam are received, the two optical signals are coupled and the coupled optical signals are transmitted to the fiber optic circulator.

[0059] The fiber optic circulator 108 is used to transmit the optical signal corresponding to the first beam and the optical signal corresponding to the second beam to the displacement control component. The fiber optic circulator is provided with an input port and an output port for the optical signal; the optical signal corresponding to the first beam and the optical signal corresponding to the second beam are transmitted to the displacement control component via the output port.

[0060] An optical fiber circulator is a multi-port non-reciprocal optical device with irreversible signal transmission direction; light can only propagate in one direction, enabling bidirectional optical signal transmission over a single optical fiber. While the optical signal can be redirected during transmission within the circulator, it must pass through the ports sequentially in one direction. An optical fiber circulator typically has three ports. In this step, the optical signals corresponding to the first beam and the second beam are input to the displacement control component from the same output port.

[0061] The displacement control component 111 is used to capture target microparticles using the optical signal corresponding to the first beam, and the target microparticles generate an excitation fluorescence signal under the illumination of the optical signal corresponding to the second beam, and the excitation fluorescence signal is transmitted to the second optical fiber coupler through the optical fiber circulator.

[0062] The displacement control component disclosed in this embodiment includes an optical fiber end cap and a position control platform for controlling the movement of the optical fiber end cap. The surface of the optical fiber end cap is configured as a three-dimensional structure (its shape can be conical). The optical signal corresponding to the first beam forms a high-order focused beam on the three-dimensional structure of the end face of the optical fiber end cap. This high-order focused beam can apply a specific optical force to microparticles, thereby achieving the capture and manipulation of microparticles. The position control platform can control the movement of the optical fiber end cap in different directions to achieve the capture of microparticles or cells.

[0063] The displacement control component disclosed in this embodiment is used to precisely control the position of the optical fiber end to capture target microparticles. The captured target microparticles emit excitation light under the excitation of the optical signal corresponding to the second beam. The excitation light emitted by the target microparticles can be transmitted to the detection component through an optical fiber circulator, enabling the detection component to perform lifetime detection on the fluorescence signal. Since the optical fiber circulator can have two output ports, the fluorescence signal can be output from the other output port and transmitted to the detection component via a second optical fiber coupler.

[0064] The detection component 110 is connected to the output end of the second optical fiber coupler 109 and is used to detect the number of photons in the excited fluorescence signal to determine the fluorescence lifetime of the target microparticle.

[0065] The optical signal corresponding to the second beam is input to the area corresponding to the detection component, serving as the detection light to enable the detection component to detect the excitation fluorescence signal.

[0066] Combination Figure 2 As shown, the light source assembly 10 further includes: a light source 101, a parallel light transmission system 102, a frequency doubling crystal element 1022, and a semi-reflective mirror 103.

[0067] Specifically, the light source 101 is used to emit a femtosecond laser beam.

[0068] The parallel light transmission system 102 includes a first lens 1021 and a second lens 1023, which together form a 4f system. The frequency doubling crystal element 1022 is located between the first lens 1021 and the second lens 1023. The first lens 1021, the frequency doubling crystal element 1022, and the second lens 1023 are arranged sequentially in the optical path of the femtosecond laser beam to parallelize and frequency double the femtosecond laser beam, thereby outputting a mixed beam containing two different wavelengths.

[0069] The semi-reflective lens 103 is disposed in the optical path of the mixed beam and is used to split the two different wavelength optical signals in the mixed beam into two beams by transmission and reflection, respectively, to obtain the first beam and the second beam.

[0070] Combination Figure 2 As shown, the light beam emitted by the light source, after passing through a frequency doubling crystal element, becomes a mixed beam containing two different wavelengths. For example, if the wavelength of the light beam emitted by the light source is 800nm, the frequency doubling crystal element multiplies the 800nm ​​light signal to obtain a mixed beam containing 800nm ​​and 400nm. After the mixed beam is reflected and transmitted through a semi-reflective mirror, two beams containing different wavelengths are obtained. For example, the mixed beam containing 800nm ​​and 400nm is split into two beams of 800nm ​​and 400nm after passing through a 400-600nm semi-reflective mirror.

[0071] Furthermore, in order to change the transmission direction of the light beam, the device is also provided with a reflector 104.

[0072] The reflector 104 is disposed in the optical path of the first beam transmitted through the semi-reflective lens 103, and reflects the first beam to the first objective lens 105.

[0073] Furthermore, the displacement control component 111 includes an optical fiber end, a microscopic imaging component 1112, and a position control platform 1111. The microscopic imaging component 1112 is used to convert the optical signal corresponding to the first beam output from the optical fiber circulator 108 into an electrical signal to capture image information within the target area; the position control platform 1111 is used to control the movement of the optical fiber end within the target area to capture target microparticles within the target area using a high-order focused beam formed on the surface of the optical fiber end.

[0074] To achieve precise manipulation of microparticles within a target area, this embodiment utilizes a position control platform to move the end face of an optical fiber, capturing the microparticles using a high-order focused beam formed on the surface of the fiber end face. In one implementation, the position control platform 1111 is a six-axis precision displacement stage. A six-axis precision displacement stage can achieve precise control and micro-displacement in the x, y, and z directions in three-dimensional space. The end face of the optical fiber is a three-dimensional structure. The three-dimensional structure of the end face can form a specific optical field distribution, localizing the optical field energy within a region far below the diffraction limit, forming a high-intensity electromagnetic field hotspot, thereby providing a large optical gradient force and achieving high-precision capture of nanoscale particles, thus improving capture accuracy. The fiber end face with the three-dimensional structure can achieve dynamic control of the surface plasmon polariton light field through the spatial movement of the probe or optical fiber. This dynamic control capability allows optical tweezers to manipulate microparticles more flexibly, meeting the needs of different experiments and applications. Furthermore, the design of the three-dimensional structure can optimize the interaction between the light field and the microparticles, improving the stability of capture. For example, by designing a suitable three-dimensional structure, the light field can be more uniformly distributed around the particle, thereby reducing the possibility of particle escape. Therefore, the displacement control component provided in this application can more accurately capture and control the movement of target microparticles.

[0075] Furthermore, the microscopic imaging components include a CCD and a high-magnification objective lens. The CCD, acting as an image sensor, converts the light signal focused by the objective lens into an electrical signal, exhibiting high sensitivity to capture weak fluorescence signals. The high-magnification objective lens magnifies and focuses the target microparticles or cells onto the target surface of the CCD, thereby improving image quality.

[0076] The target microparticles can be microparticles or cells in a solution environment. Therefore, in this embodiment, the six-axis precision displacement stage drives the controllable optical fiber to move in order to capture the microparticles.

[0077] In one implementation, the detection component 110 includes a photomultiplier tube 1101 and a time-correlated single-photon counter 1102. The photomultiplier tube 1101 amplifies the received excitation fluorescence signal and the optical signal corresponding to the second beam. The time-correlated single-photon counter 1102 measures the number of photons in the received excitation fluorescence signal to determine the fluorescence lifetime of the target microparticle based on the number of received photons.

[0078] Photomultiplier tubes (PMTs) can amplify minute signals by changing their frequency from low to high. Because PMTs have high sensitivity, they can detect extremely weak light signals and have a fast response speed, as well as capture rapidly changing light signals. Therefore, the use of PMTs can improve detection accuracy.

[0079] Time-correlated single-photon counters enable precise measurement of fluorescence decay by recording the arrival time of individual fluorescent photons. In fluorescence lifetime detection, they can capture weak fluorescence signals and convert them into time-correlated electrical signals, providing a basis for subsequent data processing and analysis.

[0080] Time-correlated single-photon counter (TCSPC) is a high-precision technique for measuring periodic photon events. Its core principle involves periodically exciting a sample with a pulsed light source, capturing individual photons to generate an analog signal, and then processing the signal to determine the photon arrival time. Discrete sampling is used to construct a time histogram to characterize the temporal distribution of the photon sequence. In the TCSPC system, the photon counter measures the detection time of a single photon and reconstructs the waveform based on individual time measurements. The TCSPC detects single photons in periodic light signals. For low-level, high-repetition-rate signals, the light intensity is typically low, and the probability of detecting a single photon within one signal period is much less than 1; therefore, the detection of multiple photons can be ignored. When a photon is detected, the time of the corresponding detector pulse is measured, and the event is collected by adding a "1" to an address in memory proportional to the detection time. After many photons, a histogram of the detection time, i.e., the waveform of the light pulse, is obtained. Based on the waveform analysis of the light pulse, the average time for the fluorescent molecule to return from the excited state to the ground state is obtained, thus determining the fluorescence lifetime. Because time-correlated single-photon counters have the advantages of ultra-high time resolution and ultra-high sensitivity, they can achieve better measurement accuracy when applied to fluorescence lifetime measurement.

[0081] To achieve better detection results, the wavelength of the femtosecond laser beam in this embodiment is 800nm. The wavelength corresponding to the first beam is 800nm, and the wavelength corresponding to the second beam is 400nm. Optionally, the focal length of the first lens and the second lens is 15mm.

[0082] The fluorescence lifetime detection device in this embodiment, combined with fiber optic tweezers, offers advantages in high sensitivity and operational flexibility for numerous invasive detection methods, such as deep human tissues. Furthermore, the captured particles and large particles can serve as quantitative drug delivery systems. Since the fluorescence lifetime of fluorescent molecules is highly sensitive to changes in various environmental factors, it can serve as a localization signal. For example, the detection device disclosed in this embodiment can realize environmental localization to a medical device prototype for targeted, quantitative drug delivery.

[0083] This invention provides a fiber optic tweezers fluorescence lifetime detection device. It splits a light beam emitted from a light source into two paths, couples the two received optical signals using a first fiber optic coupler, and transmits the coupled signals to a connected fiber optic circulator. The circulator then transmits the two optical signals to a displacement control component. The displacement control component uses one optical signal to capture a target microparticle. Under the illumination of the corresponding optical signal from the other beam, the target microparticle generates an excitation fluorescence signal. This excitation fluorescence signal is transmitted to a detection component via the fiber optic circulator and a second fiber optic coupler. The detection component detects the number of photons in the excitation fluorescence signal to determine the fluorescence lifetime of the target microparticle. This invention allows for the flexible manipulation of microparticles while detecting their fluorescence lifetime. Furthermore, this invention is simpler and more efficient, suitable for ultrafast signal detection in precision large instruments.

[0084] Secondly, this application provides a method for detecting fluorescence lifetime, applied to the aforementioned fiber optic tweezers fluorescence lifetime detection device, such as... Figure 3 As shown, the method for detecting fluorescence lifetime specifically includes:

[0085] Step S1: The first objective lens and the second objective lens respectively collect the optical signals of the first beam and the second beam emitted by the light source assembly, and transmit the collected optical signals to the first fiber coupler; the first beam and the second beam have different wavelengths.

[0086] The light source assembly emits two beams of light, each with a different wavelength and function. The first beam is used to form a high-order focused beam on the end face of the optical fiber to capture the target microparticles, while the second beam is used to excite the captured target microparticles to emit excitation fluorescence.

[0087] Specifically, in order to enable the light source assembly to emit two beams of different wavelengths, further, before the step of the first objective lens and the second objective lens respectively collecting the light signals of the first beam and the second beam emitted by the light source assembly, the method further includes:

[0088] Step S01: The light source emits a femtosecond laser beam.

[0089] Step S02: The parallel light transmission system set in the optical path of the femtosecond laser beam performs parallelization and frequency doubling on the femtosecond laser beam, and outputs a mixed beam containing two different wavelengths.

[0090] Step S03: The semi-reflective lens placed in the optical path of the mixed beam splits the two different wavelengths of light signals in the mixed beam into two beams, resulting in the first beam and the second beam.

[0091] Step S2: The first fiber coupler couples the optical signals corresponding to the first beam and the second beam received, and transmits the coupled optical signals to the displacement control component via the fiber optic circulator.

[0092] Both the first and second objectives are connected to the first optical coupler. When the first and second objectives receive the optical signals corresponding to the first and second beams, respectively, they input the received signals to the first optical coupler. A fiber optic circulator is connected downstream of the first optical coupler, and the first optical coupler transmits the coupled light of the optical signals corresponding to the first and second beams to the fiber optic circulator. The coupled beam is then transmitted to the displacement control component via the fiber optic circulator.

[0093] Step S3: The displacement control component uses the optical signal corresponding to the first beam to capture the target microparticles. The target microparticles generate an excitation fluorescence signal under the illumination of the optical signal corresponding to the second beam. The excitation fluorescence signal is transmitted to the detection component through the fiber optic circulator and the second fiber optic coupler.

[0094] The displacement control component consists of a CCD and a six-axis precision displacement stage. This displacement control system can control the movement of optical fibers with three-dimensional structures on the fiber end face to capture tiny particles or cells in a solution environment.

[0095] Step S4: Use the detection component to detect the number of photons in the excited fluorescence signal to determine the fluorescence lifetime of the target microparticle.

[0096] The detection components include a photomultiplier tube and a time-correlated single-photon counter, forming an ultrafast signal detection system. The photomultiplier tube is used to amplify the excitation fluorescence signal, and the time-correlated single-photon counter is used to detect the fluorescence lifetime of tiny particles or cells.

[0097] The detection device and method provided in this application utilize fiber optic couplers to couple signals onto optical fibers, resulting in high system optical coupling efficiency. Furthermore, the use of fiber optic circulators enables optical path multiplexing, allowing for multi-point detection and simultaneous manipulation of microparticles and detection of fluorescence lifetime. Because this device is based on a single multimode fiber loop for multi-wavelength incident light, it overcomes the limitations of structures requiring multiple single-mode fibers or spliced ​​fiber types, which restrict operational flexibility and improves operational efficiency and accuracy.

[0098] Other embodiments of the present invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein.

[0099] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0100] It is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A fiber optic tweezers fluorescence lifetime detection device, characterized in that, include: A light source assembly for emitting a first beam and a second beam with different wavelengths; The first objective lens and the second objective lens are respectively disposed in the optical paths of the first beam and the second beam, and are used to collect the optical signals of the first beam and the second beam, and transmit the collected optical signals to the first fiber coupler; The first fiber coupler is used to couple the optical signals corresponding to the first beam and the second beam received, and to transmit the coupled optical signals to the connected fiber optic circulator. The fiber optic circulator is used to transmit the optical signal corresponding to the first beam and the optical signal corresponding to the second beam to the displacement control component. The displacement control component has an optical fiber end for capturing target microparticles. The target microparticles are captured by a high-order focused beam formed by the optical signal corresponding to the first beam at the optical fiber end. Under the illumination of the optical signal corresponding to the second beam, the target microparticles generate an excitation fluorescence signal, which is transmitted to the second optical fiber coupler via the optical fiber circulator. The detection component is connected to the output end of the second fiber coupler and is used to receive the excitation fluorescence signal output by the second fiber coupler, and to detect the number of photons in the excitation fluorescence signal to determine the fluorescence lifetime of the target microparticle.

2. The fiber optic tweezers fluorescence lifetime detection device according to claim 1, characterized in that, The light source assembly includes: a light source, a parallel light transmission system, a frequency doubling crystal element, and a semi-reflective mirror; The light source is used to emit a femtosecond laser beam; The parallel light transmission system includes a first lens and a second lens, which together form a 4f system. The frequency doubling crystal element is located between the first lens and the second lens. The first lens, the frequency doubling crystal element, and the second lens are arranged sequentially in the optical path of the femtosecond laser beam to parallelize and frequency double the femtosecond laser beam, and output a mixed beam containing two different wavelengths. The semi-reflective lens is disposed in the optical path of the mixed beam to split the two different wavelength optical signals in the mixed beam into two beams by transmission and reflection, respectively, to obtain the first beam and the second beam.

3. The fiber optic tweezers fluorescence lifetime detection device according to claim 2, characterized in that, The system is also equipped with a reflector; The reflector is positioned in the optical path of the first beam transmitted through the semi-reflective lens, and reflects the first beam to the first objective lens.

4. The fiber optic tweezers fluorescence lifetime detection device according to claim 1, characterized in that, The displacement control component includes an optical fiber end cap, a microscopic imaging component, and a position control platform; The microscopic imaging component is used to convert the optical signal corresponding to the first beam output from the fiber optic circulator into an electrical signal to capture image information within the target area. The position control platform is used to control the movement of the optical fiber tip within the target area, so that the optical fiber tip captures the target microparticles within the target area.

5. The fiber optic tweezers fluorescence lifetime detection device according to claim 4, characterized in that, The position control platform is a six-axis precision displacement stage, and the end face of the optical fiber tip has a three-dimensional structure.

6. The fiber optic tweezers fluorescence lifetime detection device according to claim 1, characterized in that, The detection components include: a photomultiplier tube and a time-correlated single-photon counter; The photomultiplier tube is used to amplify the received excitation fluorescence signal; The time-correlated single-photon counter is used to measure the number of photons in the received excitation fluorescence signal, so as to determine the fluorescence lifetime of the target microparticle based on the number of received photons.

7. The fiber optic tweezers fluorescence lifetime detection device according to claim 2, characterized in that, The wavelength of the femtosecond laser beam is 800nm.

8. The fiber optic tweezers fluorescence lifetime detection device according to claim 1 or 7, characterized in that, The wavelength corresponding to the first beam is 800nm, and the wavelength corresponding to the second beam is 400nm.

9. The fiber optic tweezers fluorescence lifetime detection device according to claim 2, characterized in that, The focal length of the first lens and the second lens is 15mm.

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